In general, an antenna device including a feed element and a non-feed element is known. Such an antenna device is disclosed in National Patent Publication Gazette No. 2005-538623, for example.
In National Patent Publication Gazette No. 2005-538623, there is disclosed a multiband antenna (antenna device) including a first arm (feed element) supplied with power and a second arm (non-feed element) connected to a ground-plane. Furthermore, in the aforementioned patent document 1, there is described that a part of the first arm and a part of the second arm are coupled to each other thereby obtaining a wide band and acquiring a multiband capability.
In general, the antenna device is installed in a communication equipment, and hence downsizing of the antenna device is required.